Radioactive Dating
Created by: Allegra Drzymkoswki

What is radioactive Dating?

• A technique used to determine the age of a rock or material by using radioactive isotopes.

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Who invented radioactive dating?

• Willard Libby, in 1947
• Calculated the half-life of C-14 to be 5,730 years.

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What is Half-Life?

• “The half-life is the amount of time it takes for half of the atoms in a sample to decay. The half-life for a given isotope is always the same; it doesn't depend on how many atoms you have or on how long they've been sitting around” (Colorado.edu/physics).

The website below shows the time it take for different isotopes to decay
http://www.colorado.edu/physics/2000/isotopes/radioactive_decay3.html

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How dose Carbon-14 dating work?

• Carbon-14 is a radioactive isotope of carbon
• Plants gain CO2 and C-14 through photosynthesis
• Animals and people eat plants
• From death, wood and bones loose C-14 as it changes from N-14 by beta decay

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How is Carbon-14 made?

• A cosmic ray collides with N-14 (7 neutrons, 7 protons)- makes C-14( 8 neutrons, 6 protons)
• C-14 is unstable

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Modern radioactive dating methods.

• Used to find the age of an fossil
• Scientists would take a piece of the fossil and burn it, creating carbon dioxide gas
• C-14 decays into N-14 emitting an electron
• A radiation counter measures the amount of electrons emitted,
• "By measuring the amount of C-12 to C-14 and comparing it to the ratio in a living organism, that can determine the age of a fossil or artifact" (ndt-ed.org)
• http://www.ndt-ed.org/EducationResources/HighSchool/Radiography/carbon14dating.htm

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A video to summarize radioactive dating:

How Dose Radiocarbon Dating Work?

Works cited

http://www.lbl.gov/abc/wallchart/chapters/13/4.html
http://australianmuseum.net.au/Radioactive-dating
http://www.colorado.edu/physics/2000/isotopes/radioactive_decay3.html
http://www.chem.uwec.edu/Chem115_F00/nelsolar/chem.htm
http://www.ndt-ed.org/EducationResources/HighSchool/Radiography/carbon14dating.htm